Multistage vacuum

ABSTRACT

A multistage vacuum includes a tank and a vacuum generating head mounted on the tank. The vacuum generating head includes a housing having multiple chambers and a gang of parallel multistage ejectors, where the respective stages of each ejector share a common chamber.

BACKGROUND

The present application relates generally to multistage vacuums and, more particularly, to a compact vacuum generating head for a multistage vacuum.

BRIEF SUMMARY OF THE DISCLOSURE

In accordance with one or more embodiments, a vacuum generating head is disclosed for a multistage vacuum. The vacuum generating head includes a housing having a first chamber, a second chamber, and third chamber and a gang of parallel ejector assemblies in the housing. Each of the ejector assemblies includes (i) an ejector nozzle in the first chamber configured to receive compressed air flow from a compressed air supply through an inlet in the housing; (ii) a first stage venturi having an inlet in the first chamber coaxially aligned with the ejector nozzle for receiving air flow from the ejector nozzle, the first stage venturi having an outlet extending into the second chamber; and (iii) a second stage venturi having an inlet in the second chamber coaxially aligned with the outlet of the first stage venturi for receiving air flow from the first stage venturi, the second stage venturi having a diffuser outlet extending into the third chamber. The housing includes a first opening in the first chamber to receive a secondary air flow from a space in which negative pressure is generated. The housing also includes a second opening with a flap valve in the second chamber to receive a secondary air flow from the space when the flap valve is open. In addition, the housing includes at least one port in the third chamber to exhaust air from the vacuum generating head.

In accordance with one or more additional embodiments, a multistage vacuum is disclosed. The multistage vacuum includes (a) a tank including a vacuum inlet and (b) a vacuum generating head mounted on the tank. The vacuum generating head includes a housing having a first chamber, a second chamber, and third chamber and a gang of parallel ejector assemblies in the housing. Each of the ejector assemblies comprises (i) an ejector nozzle in the first chamber configured to receive compressed air flow from a compressed air supply through an inlet in the housing; (ii) a first stage venturi having an inlet in the first chamber coaxially aligned with the ejector nozzle for receiving air flow from the ejector nozzle, the first stage venturi having an outlet extending into the second chamber; and (iii) a second stage venturi having an inlet in the second chamber coaxially aligned with the outlet of the first stage venturi for receiving air flow from the first stage venturi, the second stage venturi having a diffuser outlet extending into the third chamber. The housing includes a first opening in the first chamber to receive a secondary air flow from a space in the tank in which negative pressure is generated. The housing also includes a second opening with a flap valve in the second chamber to receive a secondary air flow from the space in the tank when the flap valve is open. In addition, the housing includes at least one port in the third chamber to exhaust air from the vacuum generating head.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a front view of an exemplary multistage vacuum in accordance with one or more embodiments.

FIG. 1B is a cross-section view of the multistage vacuum taken generally along line B-B of FIG. 1A.

FIGS. 2A and 2B are perspective views of the vacuum generating head of the multistage vacuum in accordance with one or more embodiments.

FIG. 2C is a front view of the vacuum generating head.

FIGS. 2D and 2E are cross-section views of the vacuum generating head taken generally along lines C-C and D-D, respectively, of FIG. 2C.

FIG. 2F is a perspective cross-section view of the vacuum generating head taken generally along line C-C of FIG. 2C.

Like or identical reference numbers are used to identify common or similar elements.

DETAILED DESCRIPTION

Various embodiments disclosed herein relate to a multistage vacuum having a compact vacuum generating head.

FIGS. 1A and 1B are front and cross-section views, respectively, of an exemplary multistage vacuum 100 in accordance with one or more embodiments.

The multistage vacuum 100 includes a vacuum generating head 102 mounted on a tank 104, in which negative pressure is generated by the vacuum generating head 102. By way of example, the tank 104 can be a 20 gallon drum assembly, though generally any type of tank can be used. The tank 104 includes a vacuum inlet 106 to which a vacuum hose (not shown) can be attached. Suction at the other end of the vacuum hose resulting from the negative pressure in the tank 104 allows material to be suctioned into the tank 104.

The material suctioned through the vacuum hose is deposited in the tank 104 and inhibited from entering the vacuum generating head 102 by a filter 108 in the tank 104.

The vacuum generating head 102 is shown in further detail in FIGS. 2A-2F. The vacuum generating head 102 includes a main unit housing 109, an exhaust housing 110, and a manifold 111. The main unit housing 109 includes a plurality of successively arranged chambers separated by chamber walls. Specifically, the main unit housing 109 includes a first chamber 112 and a second chamber 114. The exhaust housing 110 includes an interior space 116, which forms a third chamber successive to the second chamber 114.

The vacuum generating head 102 includes a gang of parallel ejectors 118. In the exemplary embodiment, there are four ejectors 118 arranged in a square array as shown in FIG. 2C. Each ejector 118 comprises an ejector nozzle 120, a first stage venturi 122, and a second stage venturi 124 arranged in co-axial alignment in series.

The ejector nozzles 120 are located in the first chamber 112. The nozzles 120 receive a compressed air flow from a compressed air supply, e.g., an air compressor (not shown) through a port 125 in the manifold 111.

Each of the first stage venturis 122 has an inlet in the first chamber 112 aligned with a respective ejector nozzle 120 for receiving air flow from the ejector nozzle 120. The first stage venturis 122 extend through the chamber wall between the first and second chambers 112, 114 such that the venturi outlets are in the second chamber 114.

Each of the second stage venturis 124 has an inlet in the second chamber 114 aligned with a respective first stage venturi outlet for receiving air flow from the first stage venturi 122. The second stage venturis 124 extend through the chamber wall between the second chamber 114 and the interior space 116 in the exhaust housing 110 such that the second stage venturi 124 outlets are in the interior space 116. The outlets of the second stage venturis 124 comprise diffusers 138.

The exhaust housing 110 includes exhaust ports 126 (shown in FIG. 2A) to exhaust air from the vacuum generating head 102.

The exhaust housing 110 can be lined with sound deadening foam 128 for reducing noise during operation.

The vacuum generating head 102 generates a vacuum in the tank 104. The vacuum generating head main unit housing 109 includes a first opening 130 in the first chamber 112 above the tank 104 to place the first chamber 112 in fluid communication with the space inside the tank 104. The first chamber 112 receives a secondary air flow from the space in the tank 104 through the opening 130.

The main unit housing 109 also includes a second opening 132 equipped with a flap valve 134 in the second chamber 114 such that the second chamber 114 is in fluid communication with the space inside the tank 104 when the flap valve 134 is open. The second chamber 114 can thereby receive an additional secondary air flow from the space in the tank 104 through the opening 132.

In operation, compressed air from the compressed air supply flows through the ejector nozzles 120 into respective first stage venturis 122. The inlets of the first stage venturis 122 have a larger cross-sectional diameter than the nozzles 120. The air leaving the nozzles 120 flows at a high velocity and consequently at a low pressure, thus generating a vacuum at the first stage venturi inlets to evacuate the first chamber 112. This draws in a secondary air stream from the tank 104 through the opening 130.

Air leaving the first stage venturis 122 then flows into the second stage venturis 124. The inlets of the second stage venturis 124 have a larger cross-sectional diameter than the outlets of the respective first stage venturis 122. This results in generation of a vacuum at the second stage venturi inlets and evacuation of the second chamber 114, drawing in an additional secondary air stream from the tank 104 through the opening 132 when the flap valve 134 is in an open position. The flap valve 134 automatically opens when there is a relatively high rate of the secondary air flow from the tank 104. The flow rate can decrease when, e.g., a significant amount of material has accumulated in the vacuum hose or the filter 108 becomes clogged, at which point the flap valve 134 automatically closes.

The second stage venturis 124 each have a diffuser 138 at their outlets to decrease the velocity of the ejected air stream, allowing the pressure to smoothly increase to the external pressure. The ejected air is exhausted from vacuum generating head 102 through exhaust ports 126.

A significant advantage of the vacuum generating head 102 in accordance with one or more embodiments is enhanced performance. Air powered vacuums are measured by three things—vacuum head, vacuum flow, and air usage. Air powered vacuums are known for producing high head. The vacuum head and vacuum flow are inversely related. If the vacuum is tuned for high flow, it has low head and vice versa. Vacuums in accordance with one or more embodiments allow both—high flow and high head. When the flap valve is open, the vacuum is a high flow vacuum. When the flap is closed, the vacuum is a high head vacuum. High head is needed when a vacuum hose becomes laden with material. As the vacuum flow drops because material is in the vacuum hose, the flap valve closes, creating higher head helping to move the material. In addition, the vacuum generating head in accordance with one or more embodiments uses less air for a comparably performing single stage pneumatic vacuum. Another significant advantage of the vacuum generating head 102 disclosed herein comprising a gang of parallel multistage ejectors, where the stages of each ejector share a common chamber (e.g., four first stage venturis 122 in a first chamber 112 followed by four second stage venturis 124 in a second chamber 114) is that the vacuum generating head 102 can be compact in size while providing high performance operation. For example, as shown in FIG. 1B, the vacuum generating head 102 does not extend beyond the outer periphery of the tank 104 on which it is mounted.

The exemplary vacuum generating head 102 shown in the figures has two stages. It should be understood however that vacuum generating heads in accordance with one or more embodiments can have more than two stages. In addition, vacuum generating heads in accordance with one or more embodiments can have more than the four parallel venturis shown in the figures. Having additional venturis enables the vacuum generating head to be shorter in overall length. In the exemplary embodiments, compressed air is used as the working fluid. In some cases, other gaseous working fluids can be used in the vacuum apparatus disclosed herein.

Having thus described several illustrative embodiments, it is to be appreciated that various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to form a part of this disclosure, and are intended to be within the spirit and scope of this disclosure. While some examples presented herein involve specific combinations of functions or structural elements, it should be understood that those functions and elements may be combined in other ways according to the present disclosure to accomplish the same or different objectives. In particular, acts, elements, and features discussed in connection with one embodiment are not intended to be excluded from similar or other roles in other embodiments.

Additionally, elements and components described herein may be further divided into additional components or joined together to form fewer components for performing the same functions.

Accordingly, the foregoing description and attached drawings are by way of example only, and are not intended to be limiting. 

1. A vacuum generating head, comprising: a housing having a first chamber, a second chamber, and a third chamber; and a gang of parallel ejector assemblies in the housing, each of said ejector assemblies comprising: an ejector nozzle in the first chamber configured to receive compressed air flow from a compressed air supply through a manifold inlet; a first stage venturi having an inlet in the first chamber coaxially aligned with the ejector nozzle for receiving air flow from the ejector nozzle, the first stage venturi having an outlet extending into the second chamber; and a second stage venturi having an inlet in the second chamber coaxially aligned with the outlet of the first stage venturi for receiving air flow from the first stage venturi, the second stage venturi having a diffuser outlet extending into the third chamber; wherein the housing includes a first opening in the first chamber to receive a secondary air flow from a space in which negative pressure is generated; wherein the housing includes a second opening with a flap valve in the second chamber to receive a secondary air flow from the space when the flap valve is open; wherein the housing includes at least one port in the third chamber to exhaust air from the vacuum generating head.
 2. The vacuum generating head of claim 1, wherein the vacuum generating head has exactly four ejector assemblies in the housing.
 3. The vacuum generating head of claim 2, wherein the four ejector assemblies are arranged in a rectangular array in the housing.
 4. The vacuum generating head of claim 1, wherein the space in which negative pressure is generated comprises a filtered space in a tank having a vacuum inlet coupled to a vacuum hose.
 5. The vacuum generating head of claim 1, wherein the flap valve automatically opens based on the rate of the secondary air flow.
 6. The vacuum generating head of claim 1, wherein the housing comprises a main unit housing and an exhaust housing connected to the main unit housing.
 7. The vacuum generating head of claim 6, wherein the first and second chambers are in the main unit housing and the third chamber is in the exhaust housing.
 8. The vacuum generating head of claim 1, wherein at least the third chamber in the housing is lined with sound deadening foam.
 9. A multistage vacuum, comprising: (a) a tank including a vacuum inlet; and (b) a vacuum generating head mounted on the tank comprising: a housing having a first chamber, a second chamber, and a third chamber; and a gang of parallel ejector assemblies in the housing, each of said ejector assemblies comprising: an ejector nozzle in the first chamber configured to receive compressed air flow from a compressed air supply through an inlet in the housing; a first stage venturi having an inlet in the first chamber coaxially aligned with the ejector nozzle for receiving air flow from the ejector nozzle, the first stage venturi having an outlet extending into the second chamber; and a second stage venturi having an inlet in the second chamber coaxially aligned with the outlet of the first stage venturi for receiving air flow from the first stage venturi, the second stage venturi having a diffuser outlet extending into the third chamber; wherein the housing includes a first opening in the first chamber to receive a secondary air flow from a space in the tank in which negative pressure is generated; wherein the housing includes a second opening with a flap valve in the second chamber to receive a secondary air flow from the space in the tank when the flap valve is open; wherein the housing includes at least one port in the third chamber to exhaust air from the vacuum generating head.
 10. The multistage vacuum of claim 9, wherein the vacuum generating head has exactly four ejector assemblies in the housing.
 11. The multistage vacuum of claim 10, wherein the four ejector assemblies are arranged in a rectangular array in the housing.
 12. The multistage vacuum of claim 9, wherein the tank further includes a filter in the space in which negative pressure is generated.
 13. The multistage vacuum of claim 9, wherein the flap valve automatically opens based on the rate of the secondary air flow.
 14. The multistage vacuum of claim 9, wherein the housing comprises a main unit housing and an exhaust housing connected to the main unit housing.
 15. The multistage vacuum of claim 14, wherein the first and second chambers are in the main unit housing and the third chamber is in the exhaust housing.
 16. The multistage vacuum of claim 9, wherein at least the third chamber in the housing is lined with sound deadening foam.
 17. The multistage vacuum of claim 9, wherein the vacuum generating head does not extend beyond the periphery of the tank.
 18. A multistage vacuum, comprising: a tank including a vacuum inlet; and a vacuum generating head mounted on the tank comprising a housing and a gang of parallel multistage ejectors in the housing, wherein respective stages of each ejector share a common chamber in the housing.
 19. The multistage vacuum of claim 18, wherein the vacuum generating head comprises a first chamber, a second chamber, and a third chamber in the housing, and wherein each ejector comprises: (a) an ejector nozzle in the first chamber configured to receive compressed air flow from a compressed air supply through an inlet in the housing, (b) a first stage venturi having an inlet in the first chamber coaxially aligned with the ejector nozzle for receiving air flow from the ejector nozzle, the first stage venturi having an outlet extending into the second chamber, and (c) a second stage venturi having an inlet in the second chamber coaxially aligned with the outlet of the first stage venturi for receiving air flow from the first stage venturi, the second stage venturi having a diffuser outlet extending into the third chamber.
 20. The multistage vacuum of claim 19, wherein the housing includes a first opening in the first chamber to receive a secondary air flow from a space in the tank; wherein the housing includes a second opening with a flap valve in the second chamber to receive a secondary air flow from the space when the flap valve is open; and wherein the housing includes at least one port in the third chamber to exhaust air from the vacuum generating head. 